Apparatus for pneumatic transporting of grain or similar material



March 18, 1958 s. W.WALL1N 2,827,333

- APPARATUS FOR PNEUMATIC TRANSPORTING OF GRAIN OR SIMILAR MATERIALFiled July 1955 INVENTOR. SVEN WERNER WALLIN AT'TYYS.

United tates Patent APPARATUS FOR PNEUMATIC TRANSPORTTNG 0F GRAIN 0RSIMTLAR MATERIAL Sven \Verner Wallin, Jonkoping, Sweden, sssignor toAktiebolaget Svenska Flaktfahriken, Stockhaim, Sweden Application July8, 1955, Serial No. 520,852

Claims priority, application Sweden July 19, 1954 3 Claims. (Cl. 302-36)The present invention relates to an apparatus for pneumatic transportingof grain or similar material in a pipe system, the material being inknown manner fed into and carried by an air current delivered by a fan.It is known that a fan, owing to the shape of its characteristic curve,operates in such a manner that the air quantity varies with thecounter-pressure, i. e. the air quantity increases upon a decrease incounter-pressure and vice versa. For common centrifugal fans also thepower consumption varies in the same way as the change in air quantity.By using centrifugal fans for pneumatically transporting the air, thequantity and also the power consumption will thus increase upon adecrease in the quantity of material and vice versa. This is changecontrary to what is desired. By reason of this increase of the airquantity caused by lowered load, not only will the power consumptionincrease resulting in increasing running costs and a risk of overloadingof the motor, but also there is a risk when transporting of materials,such as grain, of damaging the same by using a high transport velocity.On the other hand, when the air quantity by reason of an increasedsupply of materials, sinks, there is, of course, a risk of shut-downbecause of accumulation of material in the conventional feeding deviceor mixing chamber since the decreasing air quantity results in acontinuous decrease in the material discharged from the feeding device.When in this manner the air velocity decreases below a certain valuethere is also a risk that the material in an uncontrolled manner isaccumulated in the pipe lines. It is an object of the present inventionto eliminate said drawbacks.

The invested apparatus consists of a feeding device having a mixingchamber suitably provided with sluicing or material supplying means andconnected to a pipe-line and a transporting fan. The invention ischaracterized in that between said mixing chamber and the fan there isarranged a volume governor, for instance a governor in accordance withthe Swedish Patent 133,723, which corresponds to my U. S. patentapplication, Serial No. 384,471 filed September 22, 1953, now Patent No.2,765,812. The governor is designed to increase the air quantity atincreasing counter-pressure towards a predetermined maximum value and toshut ofi the supply of material by stopping the sluicing means at theposition of the floating body of the governor corresponding to apredetermined maximum counter pressure.

The invention will now be more closely described with reference to theaccompanying drawing, showing an exemplifying embodiment of theapparatus.

In the drawing 1 designates a centrifugal transporting fan and 2 is avolume governor arranged between the outlet of the fan and a feedingdevice for the material consisting of a hopper 8, a sluicing wheel 7with motor 6, a pressure chamber 9, a mixing chamber 11 and an airdistributing means arranged between the last menice tioned two spaces.12 designates a transporting pipe leading from the mixing chamber 11.The above mentioned volume governor 2 comprises a floating throttlevalve 3, the design of which is made in accordance with the earliermentioned Swedish Patent No. 133,723 and a guiding rod 4. Adjacent tothe rod 4 there is applied a sensitive means 5, for instance a so-calledmicro-switch arranged to be influenced by said rod in order to shut offthe supply of material at a certain predetermined position of thefloating body. In the illustrated embodiment of the means 5 acts uponthe driving motor 6 for the sluicing wheel 7.

The invention is not limited to the use of volume governors of thedescribed kind as other types of governors can be used within the scopeof the invention.

What I claim is:

1. Apparatus for transporting grain or similar material in a gaseousmedium, comprising in combination a mixing chamber for the material andthe gaseous medium, a conduit for the conveyance of the gaseous mediumhaving therein suspension of the material, a feeding device forsupplying said material to the mixing chamber and a fan for supplyingthe gaseous medium to said mixing chamber and a flow governor betweensaid fan and said conduit to regulate the volumetric flow of the mediumto said mixing chamber in accordance with changes in the counterpressure in the conduit, said flow governor comprising a floatingthrottle valve responsive to said counter pressure and including meansfor automatically stopping said feeding device operable upondisplacement of said floating throttle valve to a position correspondingto a predetermined maximum counter pressure.

2. Apparatus according to claim 1 in which said stopping means consistsof a switch having an operator in the path of movement of said floatingthrottle valve operable by said valve to interrupt the power supply tothe feeding device.

3. Apparatus for transporting grain or similar materials in a gaseousmedium comprising in combination a mixing chamber for the material andthe gaseous medium, a substantially constant speed fan for supplying thegaseous medium to said mixing chamber positioned remote from said mixingchamber, a pressure chamber interconnecting said fan and said mixingchamber, a flow governor in said pressure chamber between said fan andsaid mixing chamber comprising throttling means responsive to thecounter pressure in said mixing chamber and operable to regulate thevolumetric flow of the medium to said mixing chamber in accordance withchanges in the counter pressure in the mixing chamber, a feeding devicefor supplying said material to the mixing chamber, and a conduitconnected to said mixing chamber for the conveyance of the gaseousmedium having therein a suspension of the material from said mixingchamber.

References Cited in the file of this patent UNITED STATES PATENTS494,375 Grigsly Mar. 28, 1893 1,450,903 Newhouse Apr. 3, 1923 2,180,379Whitfield Nov. 21, 1939 2,544,054 Smith Mar. 6, 1951 2,695,815 BergstromNov. 30, 1954 2,727,792 Bearer Dec. 20, 1955 2,765,812 Wallin Oct. 9,1956 2,770,584 Ray Nov. 13, 1956 FOREIGN PATENTS 1,074,419 France Oct.5, 1954

